title: Tribbles-2 is a novel regulator of inflammatory activation of monocytes.
abstract: Inflammatory activation of monocytes is an essential part of both innate immune responses and the pathogenesis of conditions such as atherosclerosis. However, the mechanisms which modulate the response of monocytes to inflammatory stimuli are still poorly understood. Here, we report that tribbles-2 (trb-2) is a novel regulator of inflammatory activation of monocytes. Down-regulation of trb-2 levels potentiates LPS-induced IL-8 production via enhanced activation of the extracellular signal-regulated kinase and jun kinase mitogen-activated protein kinase (MAPK) pathways. In keeping with this, the endogenous level of trb-2 expression in human primary monocytes is inversely correlated to the cell's ability to produce IL-8. We show that trb-2 is a binding partner and a negative regulator of selected MAPKs. The potential in vivo relevance of these findings is highlighted by the observation that modified low-density lipoprotein profoundly down-regulates trb-2 expression, which may, in turn, significantly contribute to the inflammatory processes in the development of vascular disease. Taken together, our results define trb-2 as a potent novel regulator of monocyte biology, controlling the activation of these cells.
authors.affiliation: Cardiovascular Research Unit, University of Sheffield, Sheffield, UK.
authors.forename: Katalin
authors.initials: K
authors.lastname: Eder
authors.forename: Hongtao
authors.initials: H
authors.lastname: Guan
authors.forename: Hye Y
authors.initials: HY
authors.lastname: Sung
authors.forename: Jon
authors.initials: J
authors.lastname: Ward
authors.forename: Adrienn
authors.initials: A
authors.lastname: Angyal
authors.forename: Michelle
authors.initials: M
authors.lastname: Janas
authors.forename: Gabriella
authors.initials: G
authors.lastname: Sarmay
authors.forename: Erno
authors.initials: E
authors.lastname: Duda
authors.forename: Martin
authors.initials: M
authors.lastname: Turner
authors.forename: Steven K
authors.initials: SK
authors.lastname: Dower
authors.forename: Sheila E
authors.initials: SE
authors.lastname: Francis
authors.forename: David C
authors.initials: DC
authors.lastname: Crossman
authors.forename: Endre
authors.initials: E
authors.lastname: Kiss-Toth
mesh_terms: D050197:Atherosclerosis / Q000209:etiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002460:Cell Line; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006801:Humans; D007113:Immunity, Innate; D016209:Interleukin-8 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000235:genetics / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000276:immunology
chemical_list: D016209:Interleukin-8; D047908:Intracellular Signaling Peptides and Proteins; D008077:Lipoproteins, LDL; D034741:RNA, Small Interfering; C032629:acetyl-LDL; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C489044:TRIB2 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases